Facilities for producing television programs typically make use of video signals from a variety of sources, such as television cameras, videotape recorders, video servers, satellite feeds, telecine equipment, character generators, and/or slow-motion recording and playback devices, for example. A video switcher (some times referred to as a production switcher or vision mixer) receives video signals from such sources and allows an operator to switch among and/or mix different signals to yield a video output signal of interest to viewers.
A typical video switcher includes one or more mix/effects engines, (M/Es) for processing video signals and associated key signals. Each M/E has receives at least one and preferably a plurality of video signals and key signals supplied via a cross-point matrix. Each key signal serves to composite a video signal. The composite video signals output by the M/Es are typically routed back to the cross-point matrix to provide for layering of video signals.
The M/Es within early generation video switchers provided a single program (PGM) and a single preview (PVW) output. Thus, a video switcher having four M/Es would have eight video outputs. Enabling personnel within a control room to observe the images associated with the program and preview outputs of each of the four M/Es of the video switcher required eight separate video monitors. Currently, some video switcher manufacturers offer M/Es with as many as 4 or 6 outputs and future generations of M/Es will have even more outputs. Thus, conventional methodology would necessitate a large number of monitors to enable monitoring of the M/E output signals. However, a limit exists on the space available in most studio control rooms and mobile trucks for monitors. Additionally, increasing the number of monitors to enable monitoring of the M/E output signals increases costs and operating complexity.